1. Field of the Invention
The present invention relates to a semiconductor element, and more particularly to an LED (light-emitting diode) chip.
2. Description of the Related Art
The light-emitting diode (LED) emits light by converting electric energy into optical energy. The LED is mainly composed of semiconductors. Of the semiconductors, those having a larger ratio of holes carrying positive electricity are referred to as P type semiconductors, and those having a larger ratio of electrons carrying negative electricity are referred to as N type semiconductors. The joint connecting a P type semiconductor and an N type semiconductor forms a PN junction. When voltage is applied to the positive electrode and the negative electrode of an LED, the electrons and the holes will be combined and emitted in the form of light.
In addition, the luminous intensity of an LED is related to the current density of a voltage applied thereto. In general, the luminous intensity increases with the increase in the current density. However, it is not easy to increase the light extraction efficiency and at the same time make the current uniformly diffused. In a conventional method, the current can be uniformly diffused by extending the electrodes. By doing so, the light-emitting area is reduced and the luminous intensity deteriorates accordingly. Conversely, if the luminous intensity is increased by reducing the light-blocking area of the electrodes, the current cannot be diffused uniformly and the effect of heat concentration will be worsened. Therefore, how to make the current density uniformly distributed without affecting the luminous intensity has become a prominent task for the industry